Method of molding hollow bodies of glass



July 19, 1938. E s 2,123,937

METHOD OF MOLDING HOLLOW BODIES 'OF GLASS Filed May 24, 1935 tllllllllllllllllili Jjweufm "I 15 while blowing or in a more or less mechanical up in the mold the hollow body from below in an 15 Patented July 19, 1938 LIETHOD OF.MOLDING HOLLOW BODIES OF GLASS Bernhard Engels, Waldenburg-Altwasser,

Germany Application May 24, 1935, Serial No. 23,289 In Germany August 7, 1934 2 Claims. (Cl. 49-85) This invention relates to a method of molding temperature of the mold by means of additional hollow bodies of glass or other fusions of silicates, heating or also cooling means. such as molten quartz, particularly with respect The practical application of the new method is to the production of hollow bodies of this class effected by moving the mold relative to the glass 5 having large diameters and requiring a. considerstream coming out of a casting vessel, i. e., by 5 able wall thickness. employing either a mold moving past the glass Such hollow bodies, e. g., tubes, cylinders, etc., stream or a stationary mold in connection with a were hitherto exclusively fashioned in accordance correspondingly moved outlet opening of the castwith methods which had the feature in common ing vessel.

that the hollow body was shaped at all points of Embodying the principle outlined above, the 10 its circumference at the same time,-so that the new method can find expression in various forms entire extent of the body was produced simuitaneof construction. ously, either by catching the molded articles by For example, it is possible to cause rotation of means of a blowing-iron and drawing them off the mold provided with a central core and to build manner and likewise by drawing off the still upward direction by means of the incoming glass plastic glass from a round pipe member, for stream which, during rotation of the mold, always instance according to the Danner or Phillips forms a new layer on the one already located in methods. the mold and unites therewith. Or the velocity Another known process consisting in blowing of rotation ay be u d preparatory to build- 20 the glass mass into a mold also provides for the ing up the body in circumferential direction, simultaneous production of the entire circumferthough this involves limitations as to the linear ence of the article to be made. dimensions of the body.

It is evident that the application of these known The method is further not limited to the pro- 5 molding methods in practical operation sets very duction of regular rotational bodies, since other narrow limits to the dimensions both as to diamshapes, preferably of course such as have a closed eter and wall thickness, which are attainable, the circumference, can be produced in the manner more so as with the increase in diameter the wall described. in which case it may be necessary to thicknesses that could still be obtained were redirect the rotary motion of the mold in a corre- 3o duced, although, as a rule, just the opposite is spo d I desirable, namely, to impart greater wall thick- Hollow bodies made according to the new ness to articles having a largerdiameter. method can be submitted to further working proc- The practical impossibility of producing hollow esses by being for instance cut up in cooled condibodies of the kind mentioned having dimensions tion to produce channels, etc.

as to diameter and wall thickness, which exceed a The device for carryi 011% t methfld ord- 35 certain limit, has therefore prevented the more ing to theinvention is differently constructed to extensive use of such hollow bodies, for instance be adapted to the different possibilities mentioned in the form of glass tubes for industrial'purposes, .above. By way of example, one form of device in spite of the demand existing therefor. for carrying out the method with respect to its, at

40 Departing in principle from the molding methpresent, most important application, namely the 40 ods hitherto in use, the present invention affords construction of a hollow body from the bottom up, the possibility of producing such hollow bodies is diagrammatically illustrated in the accompanywith diameters and wall thicknesses of practi- 'ing drawing, in which Figure 1 is a side view of cally any desired size by providing a shaping the device partly in section, and Fig. 2, a plan 5 -method according to which the body is'not built thereof. up simultaneously at all points of its circumfer- Referring to the drawing, a is the rotary mold ence but successively, i. e., by applying layers of Y provided with the central core b and rotated by a fresh glass to those in the mold or to those being suitable drive 0 through the medium of belt'transalready in a shaped condition. mission or the like about a vertical shaft d in such It has been found that if the glass mass running a way that the hollow space e of the mold a is 50 out of a container into the mold is applied in such guidedunder and past the outlet f of the vessel layers, a perfectly homogeneous union thereof containing the glass mass. The supplementary with the mass positioned already in the mold is heating means for the mold a, which may be effected, provided the latter mass is prevented needed, are not shown. a

from cooling in the meantime as by regulating the If the method is to be carried out by keeping the 55 mold a stationary and rotating instead the outlet for the glass mass, the construction of the device will be reversed accordingly.

The after-treatment of the molded articles is effected in accordance with the usual methods in glass-making by cooling and hardening if necessary.

The method according to the invention afiords the glass industry extensive new opportunities in various fields. For example, it will now be possible to manufacture numerous objects which, owing to the difficulties connected with shaping as described, could not be made from glass hitherto, such as pipings for the chemical industries, for draining and other agricultural purposes, etc., particularly 'for purposes where the corrosion resisting quality of glass affords special advantages, especially if fragility is reduced to a minimum by subsequent hardening. New possibilities are further provided for the molding of numerous objects which hitherto had to be produced according to other methods and which can now be made from the bodies built up according to the invention, which serve as blanks.

I claim:-

1. A method of molding hollow bodies of glass or other silicic fusions of relative large diameter and corresponding proportionate wall thickness, which consists in providing a mold having a mantle and a core spaced therefrom and rigid therewith, pouring molten glass into such space from above the latter and in efiecting rotational movement between the point of pouring and the mold of such degree of rotation as to cause the glass to be successively laid in layers each engaging the mantle and core andito simultaneously weld each layer to the next succeeding layer.

2. A method of molding hollow bodies of glass or like material which consists in pouring molten glass into a defined space of ring-like form and in effecting relative rotation between the pouring point and the defined space at such speed as to cause the glass to be laid into successive layers, the temperature of a laid layer being such that same is simultaneously welded 'to the succeeding layer.

BERNHARD ENGELS. 

